The present invention relates to a system for covering a portion of a fitting or connector on a medical device or other apparatus through which fluid is transferred. The present invention is especially suitable as a cap and male Luer lock connector combination for a Luer lock type of fluid transfer device such as a hypodermic syringe.
One conventional type of syringe is a disposable syringe which is typically manufactured from inexpensive thermoplastic material, such as polyethylene or the like. Such syringes may have a standard end fitting for releasably receiving a hub from which a hollow, metal needle projects. In particular, such syringes typically have a 6% Luer taper conical nozzle fitting with a surrounding annular collar that has a double-start, right-hand, internal thread as shown in FIG. 1 of Part 2 of the International Standard ISO 594-2 (First Edition, 1991 05-01, Reference No. ISO 594-2: 1991(E)) as published by the International Organization for Standardization, Case postale 56, CH-1211 Genxc3xa8va 20, Switzerland.
The needle to be attached to the syringe end fitting projects from a molded hub having a pair of laterally extending lugs which are adapted to threadingly engage the double-start thread in the fitting collar. The molded hub defines a tapered female configuration for receiving the tapered conical nozzle of the syringe fitting as the hub is screwed into the syringe collar. Such an assembly has long been widely used.
The syringe may be prefilled. The prefilled syringe barrel is typically distributed without the needle attached, but with a cap or cover over the projecting nozzle.
It is, of course, desirable to provide such a prefilled syringe to the ultimate user with the fluid product contained in the syringe in a sterile condition. It is also desirable to ensure that the syringe nozzle is maintained in a sterile condition prior to attachment of the hub-mounted, hollow needle to the syringe nozzle.
While various syringe cap or cover designs are in use or have been proposed, it is difficult to provide a cap that maintains sterility of the syringe nozzle and surrounding collar structure in various applications and under a variety of circumstances. It would be advantageous to provide an improved cap which would maintain sterility of the threaded space within the annular collar surrounding the conical nozzle in addition to maintaining the sterility of the nozzle itself.
Some drugs, particularly protein based drugs, are advantageously stored in silicone-free containers. It would be beneficial if such an improved cap could accomplish a sealing function without the need for silicone lubricating/sealing oil. It would be beneficial for such an improved cap to have a lower potential for extractables. It would be beneficial for such an improved cap to be amenable to recycling.
Further, it would be beneficial if such an improved cap would evidence a prior removal, i.e., provide tamper evidence, after sterilization.
It would be advantageous to provide an improved cap for not only syringes but for other Luer connections as well.
In addition, it would be desirable to provide an improved cap which would provide improved sealing features without requiring more difficult or complicated installation and/or removal procedures.
Such an improved cap should also preferably accommodate manufacture from a relatively inexpensive material with relatively inexpensive manufacturing techniques so that the cap can be a low-cost, disposable item.
The present invention provides an improved cap which can accommodate designs having the above-discussed benefits and features.
A heat-set, tamper-evident seal arrangement of the present invention includes a first part, such as a cap, having an annular open sealing channel and a second part, such as a syringe or fitting, having a sealing lip surrounding a tapered annular surface. When the first and second parts are engaged together to form a seal, an inside leg of the open sealing channel is deflected outwardly by the tapered inside annular surface, and the sealing lip is deflected inwardly by an outside leg of the open channel. The sealing lip thereby axially overlies a portion of the inside leg.
The first and second part are subjected to high temperatures during a heat sterilizing procedure. The deflected or deformed sealing lip and the inside leg of the sealing channel are xe2x80x9cheat-setxe2x80x9d into their bent or stretched shapes. That is, the plastic material of the sealing lip and the inside leg of the sealing channel is subjected to a sufficiently high temperature to eliminate the residual resilient bending stress caused by the installation of the first part to the second part, i.e., the parts are stress relieved. The deflected or deformed sealing lip and the inside leg of the sealing channels assume a relaxed condition. After being heat-set by sterilizing, the first part can be removed from the second part only by resilient deflection of the heat-set deformed sealing lip and inside leg. However, after removal, the sealing lip and inside leg return to their deformed positions. At their deformed positions, the sealing lip and the inside leg of the open sealing channel mutually interfere to prevent reinstallation of the first part to the second part. Thus, a tamper evidence function and a reuse prevention function are provided.
A cap and male Luer fitting or connector according to a preferred embodiment of the present invention includes a cap having a skirt with a V-shaped annular sealing channel at a distal end thereof open toward the male Luer fitting. The male Luer fitting includes a sealing lip which is sized to be captured and deflected inwardly within the annular sealing channel as the cap is screwed tightly onto the connector. An inside annular leg, or cap seal ring, of the V-shaped annular sealing channel is deflected outwardly.
By heat sterilizing the tightly assembled cap and male Luer fitting, the sealing lip and V-shaped annular sealing channel are heat-set in their deflected postures. A portion of the sealing lip overlies the cap sealing ring in an axial direction. After removal of the cap, the heat-set deflected posture of the sealing lip and V-shaped annular channel have portions which mutually interfere in an axial installation direction to prevent reinstallation of the cap onto the male Luer fitting.
A cap of the present invention may be employed on any type of device having a fluid transfer connector. The cap is particularly useful for sealing a connector that has a nozzle with a surrounding annular collar. The cap is especially suitable for a 6% Luer tapered conical nozzle fitting with a surrounding annular collar that has a generally cylindrical exterior surface of a predetermined outer diameter and that has a double-start, right-hand, internal thread.
It is presently contemplated that a preferred, commercial embodiment of the cap of the present invention will be intended for use on a conventional male Luer lock syringe fitting. Also, the cap can be used for Luer access vials, sets, etc.; irrigation bottles; or ports on flexible bags.
The cap comprises a structure of resilient material. In a preferred embodiment, the cap is molded as a unitary structure from a plastic material. The structure of the cap may be characterized as having three basic portions: (a) an end wall, (b) an annular, inner sleeve with a male thread form, the sleeve extending from the end wall, and (c) an annular, outer skirt extending from the end wall. An annular receiving channel is defined between the outer skirt and inner sleeve.
The inner sleeve male thread form is for engaging the surrounding annular collar internal thread of the male Luer connector. The outer skirt includes the open V-shaped cross-section annular channel at its free edge opposite the end wall.
The male Luer connector, as a separate piece connector, includes an annular flange coaxially surrounding the annular collar. Extending from the annular flange, coaxially around the collar, is the sealing lip. The sealing lip is arranged to interfit within a crevice formed by a V-shaped cross-section annular sealing channel as the male Luer connector and cap are engaged. The collar internal thread engages the male thread form of the annular inner sleeve of the cap. The connector has a tapered annular surface which stretches and deforms the cap seal ring outwardly, which in turn bends the engaging sealing lip inwardly. During heat sterilization, the cap seal ring and the sealing lip are heat-set into this deformed and axially overlapping condition. After separation of the cap from the male Luer connector, the deformed sealing lip and cap seal ring axially interfere which prevents reinstallation of the same cap (or a new cap) to the male Luer connector.
At least a portion of the inner sleeve of the cap has an inner surface for sealingly engaging the nozzle of the connector. In a preferred embodiment, the cap inner sleeve has an inner surface which provides an annular gap around an outer surface of the nozzle. The nozzle is sealed closed at its open end against the end wall of the cap.
The cap can be cost effectively manufactured and easily installed. The cap seals without the use of silicone. The cap and connector fitting can be easily recycled.
Numerous other advantages and features of the present invention will become readily apparent from the following detailed description of the invention, from the claims, and from the accompanying drawings.